Means for intermittently feeding stock



y 1, 1951 w. B. EWING ETAL 2,550,680

MEANS FOR INTERMITTENTLY FEEDING STOCK 2 Sheets-Sheet 1 Filed Feb. 24,1949 FIG. 2

FIG. 5

(Ittomeg WALKLEY B. EWING STUART W T A ER l! FIG. 9

May 1, 1951 w. B. EWING ETAL MEANS FOR INTERMITTENTLY FEEDING STOCK 2Sheets-Sheet 2 Filed Feb. 24, 1949 FIG. 3

Ennentor WALKLEY B. EWING STUART W. THAYER 6 Gtkorueg -te a fabricatingmachine.

.ticularly designed to complete a large number -mored by a ratchetmechanism.

Patented May 1 1 951 UNITED STATES ATENT OFriQE MEANS For; INTESlRihgIZEIgENTLY FEEDING Walkley B. Ewing, Grand Rapids, Mich, and Stuart-W. Thayer, Melrose, Mass, as'signors to EwingDevelopmcnt Company, GrandRapids, Mich, a, corporation of Michigan Appiication February 24, 1949,Serial No. 78,126 4 Claims. (C1. 2712.1)

1 This invention relates to the intermittent feeding of stock to afabricating machine and more particularly to a feeding mechanism capableof rapidly, accurately and intermittently feeding sheet or strip stockin short segments This device is par! of feeding cycles per second.

Fabricating machines have for many years Yhad a capacity far greaterthan the ability of 1 existing feeding machines to supply them,particuiarly where. the feeding operation must be both rapid andintermittent. Thus, the capacity of thefabricating machine has beenlimited by the. capacity of" the feeding mechanism.

Although the problem of rapidly feeding short I lengths of material hasexisted for many years and many solutions have been proposed for the fcomplex problems involved, each of these solu-1 tions has had certaininherent disadvantages. 1 Among these disadvantages has been the factthat feeding machines constructed according to heretofore existingdesigns are too slow in their operation. Where the feed intermittent,re=-,

sulting in a complete cessation in the movement of the stock and thestock impelling mechanism between each feeding operation, the inertia ofl the feeding or impelling mechanism is of such magnitude that rapidwear results to the ma-' ,chine parts.

This is true even under greatly reduced operating speeds. Where rollersare employed to impel the material, it is necessary to make them massivein order to insure an effective. frictional contact with the stock andconsequently their inertia factor is high. The resulting rapidconcentration of stresses imposes excessive strains upon the operatingmechanism, wearing out clutches, gears and motors. The same observationis true in the case of the other types of impelling mechanism, such as aclamp In additionto the inertia factor of the feeding mechanism, thereis the inertia of the stock itself. This is a negligible factor at slowspeeds but increases to quite appreciable proportions as the operationis accelerated, even though thin gauge stock is involved. The inertia ofthe stock results in slippage between the stock and the impellingmechanism causing scoring of the stock surface, especially where smoothsurfaced, soft metals, such as aluminum, are involved.

Of greater importance. than the factor of wear on the machine parts anddamage to the stock is the fact that even under reduced operating speedsthe feeding operation is frequently mac 2) curate. Previously devisedmechanisms could not guarantee the identical length of material beingfed to the fabricating machine at each feeding cycle. This resulted ininferior products and. a large loss in scrap. Particularly is this aproblem in the fabrication of a product involving a large number ofpunching operations on a single sheet whereby any one serious imperfecetion destroys the value of the entire sheets. So important is thisproblem of accuracy that it was necessary to reduce the operating speedof the fabricating machine to that at which the. feeding mechanism couldoperate substantially accurately rather than to attempt to obtain thefabricating machines full capacity. The inertia impossible.

To overcome these difiiculties it was necessary to redesign completelythe feeding mechanism and to develop one operating upon an entirelynovel principle.

We have accomplished this objective by the construction of a feedingmechanism of extreme simplicity in which a substantial portion of theimpelling force for feeding the stock is generated by the inherentresiliency of the stock itself. The. remainder of the force necessary toimpel the stock is created by a pressure of constant application. Thus,the impelling force is ready for instantaneous operation each time thestock is released for movement. The necessity of activating heavyrollers and clamps is eliminated.

It is, therefore, a primary object of our invention, to provide a stockfeeding mechanism utilizing an impell-ing force generated in part by thestock itself.

It is an additional object of our invention to provide a stock feedingmechanism capable of rapid, successive, intermittent feeding cycles.

It is a further object of our invention to provide a stock feedingmechanism capable of rapidl-y feeding an accurate length of stock duringeach feeding cycle.

It is a further additional object of our inven tion to provide a stockfeeding mechanism of simpledesign and having a capacity for dependableoperation throughout a long period of use.

Other objects and purposes of our invention will be immediately seen bypersons acquainted with the problems of rapidly feeding fabricatingmachines upon reading the following specification and the accompanyingdrawings, in which:

Figure l is a side elevation view of our improved stock feedingmechanism showing a fragmentary portion of the fabricating machine indetail.

Figure 2 is a top view of our improved stock feeding mechanism.

Figure 3 is an enlarged side elevation view of the stock impelling armof our improved stock feeding machine.

Figure 4 is an enlarged view of the arch size control arm of ourimproved stock feeding mechanism.

Figure 5 is a fragmentary sectional view of the elevated guideway of ourimproved stock feeding mechanism taken along the plane VV of Figlife 2.

Figure 6 is an enlarged fragmentary sectional view of the fabricatingmachine shown in Figure 1 in the region of the punch.

Figure 7 is a side elevation view of a modification of our invention notshowing the arch size control arm.

Figure 8 is a top View of the modification of our invention shown inFigure 7.

: Figure 9 is a fragmentary front elevation view of the modification ofour invention shown in Figure '7.

For the purpose of carrying out our invention, it is necessary to usestock having a degree of inherent resiliency and capable of being forcedinto the shape of an arch without injurious effect. It should be in theform of sheets or thin rods, but cannot be material having a structuralshape such that fiexion is difficult or impossible. Further, ourinvention is designed to operate with stock supplied in long continuoussheets rather than short sections.

In executing the objects and purposes of our invention, we have providedan intermittently operated stock uncoiling device of substantiallyconventional design having cooperating therewith means creating an archor bubble of stock. Means are provided to apply a constant pressure onthe arch of stock urging it to collapse. In addition; we have providedmeans for controlling the minimum and maximum sizes of thearch.

a In" the fOllOWing description the terms upwardly and downwardly arefrequently used and are to be taken as upwardly in the direction asshown in Figure l and downwardly away therefrom; The terms forwardly andrearwardly are also frequently used and are to be taken as forwardly inthe direction in which the stock moves, 1. e., toward the fabricatingmachine, and rearwardly away therefrom.

- Referring now to the drawings in greater detail, the numeral indicatesa frabricating machine operatively associated with a stock unwinding andsupplying mechanism '2 by means of an elevated guideway 3. Thefabricating machine receives the sheet of stock l through the opening 5.Forward motion of th stock 4 is checked by the stop 6 and thereafterprevented, during the operating cycle of the machine, by the clamp 1.The material is then cut and off-set by the die 8 and upon release bythe clamp I the sheet of stock moves forwardly again until the edge ofthe uncut stock contacts the stop 6. It is thus seen that thefabricating machine I requires a stock feeding mechanism capable ofrapid, in-

termittent feeding of sheet stock in short segments. The exactconstruction and operation of thefab'ricating machine are not'presentedin detail "since they are fully described and shown in co-pendingapplication No. 688,302, filed August 3,'1946,'entitled Means forControlling the 4 Advancement ofStock, filed as a continuationin-part ofapplication No. 488,612, now Patent No. 2,405,198.

The stock supplying mechanism includes a power driven track 9intermittently operated by a -motor iii. The roll of stock I! rests onthe track 9 and unrolls whenever the upper portion of the track 9 iscaused to move rearwardly. Substantially above the roll of stock 9 l area pair of horizontally positioned rolls l2 including a driver [3 and anidler i i. A motor It provides power for intermittent operation of thedriver [3. The stock 4, passes through a loop l5 between the roll ofstock H and the rolls l2. The stock 4 passes between the driver l3 andthe idler [4 with sufiicient frictional bearing with the driver l3 thatrotation of the driver will cause the stock A to move forwardly. Theloop l5 varies in size between the minimum loop l5a and the maximum loopl5b.

A pair of followers ll, rigidly mounted to the. rod l8 rotate the rod [8as the size of the loop l5 varies between its maximum and minimumlimits. A limit switch i9, controlling the power circuit for the motorIt, is operatively attached to one end of the rod 18 and operates inresponse to the rotation of the rod. A coil spring 20 mounted onone endof the rod I8 forces the followers 11 upwardly against the loop of stockl5.

Forwardly of the rolls l2 the stocks enters the elevated guideway 3which consists of a flat bed 2| and side rails 22. The side rails 22 attheir upper ends are each equipped with a flang 23 directed toward thecenter of the elevated guideway 3 and extending over the edge portionsof the stock 4. If it is so desired, the flanges 23 may be eliminatedand the entire width of the top' of the guideway 3 covered by a sheet.At a point between the fabricating machine I and the rolls l2 a bubblearea 24 is provided by elimination of the flanges 23 for a substantialdistance longitudinally of the elevated guideway 3, leaving the stock 4free to arch upwardly. This bubble area 24 is shown as substantiallymidway between the fabricating machine l and the rolls l2, although itmay be placed anywhere along the elevated guideway 3. Preferably,however, it is placed adjacent the fabricating machine I, to reduce theamount of frictional drag on the stock 4 between the bubble area 24 andthe fabricating machine I. A pair of upwardly standing ears 25 areprovided at each end of the bubble area 24 on which are mounted,transversely of the elevated guideway 3, a pair of free rollers 26, oneon the forward end and one on the rearward end of the bubble area 24.For reasons more fully explained hereinafter, the stock 4 is caused todevelopsan arch or bubble 2? between the free rollers 2 Substantiallyrearwardly of the bubble area 24 a rod 28 is rigidly mountedtransversely to the elevated guideway 3 by means of the studs 29.Pivotally mounted on the rod 28 are the stock impelling arm 36 and thearch size control lever 3!.

The stock impelling arm 30 includes a shoe 32 and a bifurcated member31. The shoe 32 is contoured on its free end to substantially fit thearch 2'1 and is mounted on its other end to a bearing 33 rotatablysupported on the rod 28. On each side of the bearing 33 is a bearing 34,rotatably mounted on the rod 28. The bearings 33 and 3d are held againstmovement axially'of the rod 28 by the collars 35 which, in turn, aresecured to the rod 28 by the set screws 36. The bifurcated member 31 ismounted on the rod 28 by means.

of the bearings 34 and, similarly to the shoe member 32, is freelyrotatable about the rod 28. Adjacent its free end, the bifurcated member31- supports a pressure member or weight 38. The pressure member 38 mayvary in size accord-- ing; to the gauge and material of the stock 4,being of increasing weight as the gauge of the stock 4 is increased. Asan example; when the stock. 4 is .016- gauge aluminum sheet; asatisfactory weightfor the pressure member 38 has been found to beapproximately five pounds. This weight, however, will vary, even for thesame stock, according, to the amount of friction generatedby theelevated guideway 3 between the bubble area 24 and the fabricatingmachine I. To overcome the necessity of maintaining a number ofpressuremembers 38, each of a different size, the pressure member38 is designedto be movable longitudinally of the bifurcated member 3'1; To accomplishthis the pressure member 38 is mounted on the bifurcated member 31 bymeans of a plate 50 and bolt When the bolt 5| is loosened the pressuremember 38 may be moved along the bifurcated member 31.

Between the bifurcated member 31 and the shoe 32 a coil spring 39 isimposed and provides theonl'y operative contact between the two parts.The spring 39 is shown as positioned between the pressure member 38 andthe end of the bifurcated member 31 and is preferably positioneddirectly above the crown or apex of the arch 21. The

pressure member 38' may be located in vertical alignment with the spring39 or somewhat for-' wardly or rearwardly of it, depending upon theamount of downward pressure required.

The control lever 31 is mounted to the rod 28 for free rotation thereonby means of the bearing 40 and is held against axial displacement on therod ZBby the collars 4| and set screws 42. The free end of the controllever 3| rests upon the arch Z'I and is equipped with a weight 43. Theweight 43 is only of sufficient size to insure substantially constantcontact between the control lever. 3I and the arch 21.

A bracket 44 rigidly mounted to the rod 28 supports'a limit switch 45rearwardly of the control leverq3I. The limit switch 45 controls theelectrical circuit energizing the motor I6. By means of the toggleformed by the interaction of the peg 46 on the bearing 40 and the lever4'1 on the limitswitch 45, the limit switch is caused to open theelectrical circuit when the arch 2! reaches a predetermined maximum sizeand to close it again when the arch 2'! reaches a certain minimum size.

The guideway 3 is equipped with vertically positioned guide rollers 43on each side of the stock 4 between the bubble area 24 and thefabricating machine I. Guide rollers may be employed rearwardly of thebubblerarea 24, but their use in this portion of the guideway 3 is notas important as their use between the bubble area 24 and the fabricatingmachine I. The guide rollers 48 are mounted by means of shafts 49extending through the fiat bed 2! on one end and through the flange 23on the other end.

Operation A sufficient. length of stock 4 is uncoiled from the roll ofstock II to permit the stock to be fed through the rolls I2. Thereafterthemotors It and I 6 are both operated. The rolls I2 will cause thestockto advance forwardly along the guide-5 way-s and into thefabricating machine I until further forward-movement ortne end of thestock controlling the motor I6, thereby stepping the rolls I2.

The powered track 9 will continue to unwind the roll of stock II, afterthe rolls I2 have ceasedto operate, until the loop I5 expands to thesize of the loop I5b. When the loop I51) has been createdthe followersI! will actuate the limit switch {9 to open the circuit controlling themotor I f Operation of the fabricating machine I- will allow a number ofshort lengths of stock to successively escape from the arch 21.

The particular fabricating machine I, illustra tively shown here as usedin cooperation with the stock feeding mechanism comprising theinvention, maybe operated up to a speed of approxi mately 300 strokesper minute. At each stroke it requires an additional .150 inch length ofnew stock, each of which lengths must be fed to the fabricating machinewithin a period of about /2'5 of a second. Further, the variation insize between each length of stock must not exceed .00] inch. The majorproblem of feeding stock at this speed involves the necessity ofovercoming the inertia of both the feeding machinery and the stock. Ourinvention accomplishes both. The creation of the arch 27 provides, bymeans of the. natural resiliency of the stock 4, a constant urg= ing ofthe stock 4 toward the fabricating machine I. This pressure isapplied tothe stock while in motion and while stationary. The arch 21 alone,however, does not generate the required force to overcome the inertia ofthe stock 4' and impel the stock with sufficient rapidity each time itis released by the clamp 1. Therefore, the pressure member 38 is used tobear down on the arch 2"! and increase the magnitude of the force withwhich the stock is urged toward thefabricating machine. Since thespeedat which the pressure member 38 will overcome its inertia andimpose its weight upon the arch 2'! is dependent upon the rate ofacceleration of a free falling body, it is seen that the movement oftheweight is too slow to be effective when the entire movement of the stockmust be accomplished within /25 of a second. Therefore, provision mustbe made to apply the downward force to the arch 2'! during this intervalwhen the movement of the pressure member 38 lags behind the necessarymovement of the stock 4. The need for application of a downward force tothe crown of the arch 21 is most critically needed at the initiation ofthe movement of the stock 4. This is when the pressure member 38 isleast effective because its" rate of acceleration is substantially zero.

This lapse is overcome by use of the coil spring 39 interposed betweenthe pressure member 38 and the shoe 32. The resiliency of the spring 39acts to apply constantly the force of, the pressure member 38 to thebubble or arch 2'! irrespective of the rapidity of the individualmovements of the arch 27. Since the spring 39 acts instantanebus- 1yupon release of the back pressure supporting the arch 21, it applies theforce of the pressure member 38 during the interval between the time theclamp 1 releases the stock 4 and the time when inertia of the pressuremember 38 is overcome. The spring 39 applies the downward pressure onthe arch 21 while the latter is in motion, and the relatively inertpressure member 38 catches up with the spring 39 during the intervalwhen the arch 21 is stationary.

As the fabricating machine I permits escapement of the stock 4 from thearch 21, the arch decreases in size until the control lever 3I' tripsthe limit switch 45 to actuate the motor IE5. Since the rolls I2 are setto feed stock to the arch 21 faster than the fabricating machine Ipermits it to escape, the arch will increase in size until the motor I6is stopped.

The imposition of the feed regulating mechanism between the rolls :2 andthe fabricating machine I permits the rolls to be operated at muchslower speed than would be possible by intermittent rotation of therolls I2 to feedthe fabricating machine I directly. Further, eachoperation of the rolls I2 moves a sufficient length of stock 4 to supplythe fabricating machine for a large number of operating cycles. Thesefactors combine to prevent slippage between the rolls I2 and the stock 4and to reduce wear upon the rolls I2 and their operating mechanism. Thestructure and design of our feed regulating mechanism is such that thefactor of wear and slippage is minor by comparison with that experiencedin previously existing designs.

The free rollers 26 provide a friction reducing means for receiving thestock 4 into the arch 21 and delivering it from the arch 21 to theguideway 3. They also insure the existence of a radius at each end ofthe arch 21 for preventing creasing of the stock 4. The guide rollers 48reduce friction between the guideway 3 and the stock 4 to facilitate therapid operation of the feeding mechanism.

It is thus seen that our invention is'capable of feeding sheet or stripstock in short, accurate segments to a fabricating machine at lr'ghspeeds. It accomplishes this by continuously maintaining a force ofsubstantially constant magnitude on the stock for impelling it towardthe fabricating machine, even though the interval between each operationof the feeding mechanism is so short that the stock is substantiallyconstantly in mo-.

tion. At the same time, it automatically controls the supply of stock tothe feeding mechanism.

The mechanism for urging the arch 21 to collapse may be modified asshown in Figures '7, 8 and 9. In the structure shown in these figuresthe free end of the shoe Illu is supported on a truck IllI curvedlongitudinally of the stock 4 to seat over the crown of the arch 21a.Rollers I02 on each end of the truck iIlI engage the surface of the arch21d. The truck IIlI is so attached to the shoe I90 that it is heldagainst movement transversely or laterally of the shoe I but is capableof tilting longitudinally of the shoe ID!) in order to assure constantcontact with the arch 21a as the arch varies in size. The truck IilI isso constructed that the rollers I02 contact the arch 21a a substantialdistance each side of the archs centerline and thereby control the shapeof the arch and the position of its centerline longitudinally of theelevated guideway. No other guides are necessary to define the arch 21a;therefore, the free rollers 26 (Fig. 2)v may be eliminated.

Above the shoe I03 and parallel to it is the rod I03 having an isoscelestrapezoidal cross section. A pressure member or weight I94 is movablymounted on the rod H13. A set screw I65 is used to lock the pressuremember I04 in any desired position on the rod I93. A plate I06 ismounted to the lower surface of the rod I03 adjacent the rods free orforward end. A coil spring Iill mounted to the plate I96 supports thefree end of the rod I03 upon the shoe I00 and truck it I The rearwardends of the rod :03 and the shoe Mt are pivotally mounted on the shaftI08. The design and construction of the shaft I08 and of the means bywhich the rod I03 and shoe I00 are mounted to it are identical to thecorresponding structure shown in Figures 2 and 3 and, therefore, are notrepeated here. The size of the arch Zia is controlled by the arch sizecontrol arm Zia having a weight 43a on its free or forward end andpivoted to the shaft IE8 at its rearward end. A limit switch 35a mountedon a bracket 45a is actuated by the arm 3Ia. The operation of the arm31a and the limit switch 45a is identical to the arm SI and limit switch45 shown in Figures 1, 2 and 4.

The particular design for the stock feeding mechanism, as described, mayeasily be modified in other ways. The control lever 3I may be eliminatedand the limit switch i5 actuated directly by the stock impelling arm 30.It is also possible to replace the pressure member 38 with aspringforcing the stock impelling arm 30 or the truck IBI down against thearch 2 This arrangement will not, however, produce quite as satisfactoryresults as are obtained with the pres sure member 38, unless the size ofthe arch 27 is maintained within narrow limits. Fluctuations in the sizeof the arch 21 within the wide ranges possible when a weight is usedwould, in the case of a spring, produce undesirable varia tions in themagnitude of the pressure applied to the arch because of the widedifference in the degree of compression imposed upon the spring.

These and other modifications may be made without departing from thespirit of our invention and it is to be understood that all suchmodifications are to be included within the hereinafter appended claimsexcept where the claims by their terms expressly provide otherwise.

We claim:

1. In means for intermittently feeding short segments of resilient,flexible stock, including a guideway, means for impelling stock alongsaid guideway, means spaced from said stock impelling means foralternately holding and releasing said stock and stock restricting meansbetween said stock impelling means and said stock holding means definingan opening through which said stock may escape from said guideway toform an arch of said stock in said opening, the improvement thereincomprising: a truck; frictionreducing members on said truck contactingsaid arch adjacent to and on each side of the crown of said arch andurging said arch to collapse; means for restraining said truck againstmovement longitudinally of said stock; a resilient member mounted onsaid truck; a pressure member supported by said resilient member wherebyupon release of said stock at said one end, said truck, resilient memberand pressure member will urge said stock out of said arch and toward thereleased and of said stock.

2. In means for intermittently feeding short segments of resilient,flexible stock, the improvement therein comprising: a guideway; means atone of the ends of said guideway for impelling said stock along saidguideway; means at the other of the ends of said guideway foralternately holding and releasing said stock; means associated with saidguideway for preventing said stock from escaping therefrom and includinga pair of guide members between which said stock may escape upwardlyfrom said guideway to form an upwardly directed arch ofsaid stockbetween said guide members; means resting upon said arch and heldagainst movement longitudinally of said stock, said means substantiallyspaced from each of said guide members; an arm of substantial lengthpivotally mounted at one of its ends and having the other of its endsspaced from and above said means resting upon said arch; a springmounted between said means resting upon said arch and said arm; a weightmounted on said arm adjacent said spring, whereby the downward pressureof said weight is transmitted to said means resting upon said arch andto said arch by said spring for urging said arch to collapse and saidstock out of said arch when said one end of said stock is released.

3. In means for intermittently feeding short segments of resilient,flexible stock, the improvement therein comprising: a guideway; means atone of the ends of said guideway for impelling said stock along saidguideway; means. at the other of the ends of said guideway for'alternately holding and releasing said stock; means associated with saidguideway for preventing said stock from escaping therefrom and includinga pair of guide members between which said stock may escape upwardlyfrom said guideway to form an upwardly directed arch of said stockbetween said guide members; a shoe of substantial length pivotallymounted at one of its ends and having the other of its ends supported onthe crown of said arch; an arm ofjsubstantial length pivotally mountedat onev of ends and having 'the other of its ends spaced from and abovethe end of said shoe supported on said arch; a spring mountedbetweensaid shoe and said arin above the crown of said arch; a weightmounted on said arm adjacent, .said spring, whereby the downwardpressure 'of said weight is transmitted to said shoe and said arch bysaid spring forrurging said arch to collapse and said stock out of saidarch when said oneend of said stock is released. f

4. In; means for intermittently feeding short segments of resilient,flexible stockas described in claim 3 wherein said weight is detachablymounted on said arm for movement longitudinally of said arm.

V W ALKLEY EWING. STUART WQTHAYER.

REFERENCES CITED The following references are ofrecord in the file ofthis patent:

UNITED STATES PATENTS Number

